The disclosed invention relates to the formation of electrically conductive circuitry on a nonconductive substrate, and is more particularly directed to a technique for selectively dissociating the localized portions of an aluminum nitride ceramic substrate or insulating layer to form electrically conductive circuitry thereon.
Hybrid circuit structures, also known as hybrid microcircuits, implement the interconnection and packaging of discrete circuit devices, and may include one or more nonconductive ceramic substrates or layers for supporting circuit elements, which may be mounted on both sides of the microcircuit. Conductor runs for interconnecting circuit elements are formed on the surfaces of the substrate or subsequent layers, and metallized vias may be provided for interconnecting circuitry on the two sides of a ceramic substrate or between layers.
Conductor runs, for example, can be formed by thick film screen printing or thin film metallization techniques, and via metallization can be provided by thick film screen printing techniques. However, as is well known, such techniques take time and require several steps. For example, thick film screen printing requires the preparation and use of silk screens and the application of conductive paste, while thin film metallization requires chemical vapor deposition, masking and etching.
A further consideration with conductor runs formed with known techniques is the inability to trim resistors to decrease resistance values. Generally, trimming of resistors with present techniques can only increase resistance values.